Understand Your Diagnosis
How is Prostate Cancer Diagnosed?
Prostate cancer is diagnosed through a prostate biopsy, a generally safe, procedure often performed in a urologist’s office. Prostate biopsies do not cause cancer to spread. Thus, you can safely “take the next step” if your doctor recommends a biopsy.
A typical biopsy samples the right and left side of the prostate 6 times. Once the biopsy tissue is obtained, the next step is for a pathologist to examine it under the microscope. To diagnose prostate cancer, pathologists typically first examine the biopsy for abnormal, cancerous cells. Cancer cells look different than normal prostate cells and an experienced pathologist can very reliably make this diagnosis. If the pathologist sees cancer, the next step is to determine its aggressiveness. This is based on the extent of the cancer (how many biopsy cores contain cancer) and the grade of the cancer (how aggressive each cell looks under the microscope).
Some urologist are now using MRIs of the prostate to help them direct the needle into suspicious areas of the prostate. This may be helpful in your case. Ask your urologist if he/she thinks a MRI guided biopsy is necessary.
What is Gleason Grading?
As normal prostate cells change to tumor cells, they have different appearances under the microscope. Today, prostate cancers are given a score or grade, which we call the Gleason Grade. The modern Gleason grading system scores cancers with a 3, 4 or 5. The pathologist first scores the most common/prevalent type of cancer that he sees under the microscope. Then he looks for the next most common type. Together this score is the Gleason sum.
For example, if a pathologist looks at a sample and sees Gleason pattern 3 as the most common pattern and then sees a rare Gleason pattern 4, he would call that tumor a 7 (3+4). If all the pathologist saw was pattern 3, then the cancer would be called 6 (3+3). The Gleason sum ranges from 6 (3+3) to 10 (5+5). Gleason 6 is the least aggressive cancer type, Gleason 7 is intermediately aggressive, and Gleason 8-10 cancer is the most aggressive. In general, cancers with lower Gleason scores are less aggressive while cancers with higher Gleason scores are more aggressive.
Staging the Disease
Knowing the stage of the disease is another key component in determining how aggressive the prostate cancer is. The clinical stage of a prostate cancer is based on what the doctor feels upon rectal exam. The stages of prostate cancer are described below. The letter “c” before the T indicates that this is what the doctor felt on “Clinical” exam.
cT1a – This is when prostate cancer is found in <5% of TURP specimen
cT1b – This is when prostate cancer is found in >5% of TURP specimen
cT1c – This is when cancer is found via transrectal biopsy and the rectal exam is normal
T2cT2a – This is when a small nodule can be felt during the rectal exam in less than half of one side of the
cT2b – This is when one side of the prostate is hard or firm
cT2c – This is when both sides of the prostate are hard or firm
cT3a –This is when a prostate cancer can be felt pushing outside of the prostate
cT3b – This is when prostate cancer can be felt invading the seminal vesicles
cT4 – This is when prostate cancer is felt invading other organs such as the rectum or bladder
In more aggressive cancers, further staging with a MRI, CT scan or bone scan can be done to determine the extent to which prostate cancer has spread beyond the area around the prostate. For example, cancer confined within the prostate would be considered localized prostate cancer whereas cancer that has started to move to surrounding areas would be considered locally advanced prostate cancer. In metastatic disease, prostate cancer grows even further outside of the prostate, typically in lymph nodes. Prostate cancer tends to move into lymph nodes in the lower abdomen and pelvis first.
Interpreting the Stage
Together, the Gleason score of the cancer and the clinical stage determine the risk or likelihood that a cancer is curable with localized treatment.
General risk groups include:
VERY LOW RISK – Low volume (Less than 2 cores), Low grade cancer (Gleason 6)
LOW RISK – Low grade cancer (Gleason 6) AND normal rectal exam (cT1c) or small nodule on rectal exam (ct2a) AND a PSA <10
INTERMEDIATE RISK – Gleason 7 cancer AND/OR PSA 10-20 AND/OR Clinical stage t2b or t2C
HIGH RISK- Gleason 8, 9 or 10 OR PSA >20 OR Clinical stage t3 or higher
Note: Several monograms have been assembled to predict the likelihood that cancer is curable with local treatment (surgery or radiation). The easiest one to use is called the Partin Tables (http://urology.jhu.edu/prostate/partin_tables.php?lk=Partin).
Knowing the stage of prostate cancer can help to determine how aggressively it needs to be treated and how likely it is to be eradicated by the available treatment options.
Types and Stages
Localized prostate cancer: The cancer is confined within the prostate.
Locally advanced prostate cancer: Most of the cancer is confined within the prostate, but some has escaped to the immediate surrounding tissues, such as the capsule or seminal vesicles.
These two types are typically stage T1 to T4. The T score describes how much the prostate cancer has spread within the prostate and its surrounding structures.
Metastatic disease: The prostate cancer is growing outside the prostate and its immediate environs, often to lymph nodes but possibly to more distant organs. Prostate cancer tends to spread first, if at all, to lymph nodes in the lower abdomen and pelvis.
Metastatic is usually stage N1 or M1. The N score describes if lymph nodes are involved with cancer, and the M score describes if cancer has spread to areas outside of the pelvis, like bone.
Determining the Stage
Several tests can help determine the stage of disease. Traditional imaging scans (CT scans, MRIs, x-rays) and more specialized imaging tests (bone scans) can often detect cancers growing outside the prostate.
Metastatic disease can also be detected through imaging studies and often in the lymph nodes as well. Cancers that spread to more distant organs tend to travel through the lymph system. During a biopsy or surgery, lymph nodes will be removed and examined for the presence of cancer cells.
Interpreting the Stage
Localized prostate cancer is generally described in terms of risk:
- Low-risk prostate cancer—clinical T1c-T2a stage, a PSA under 10 ng/dl, and a Gleason sum of under 7. These men have a very low risk of dying from prostate cancer and generally do well with most forms of therapy. This is the most common form of prostate cancer.
- High-risk prostate cancer—clinical T2c and higher stage, Gleason 8 or higher grade, and PSA over 20 ng/dl. These men have a much higher risk of recurrence with surgery or radiation or surveillance, and often benefit from more aggressive combination approaches.
- Intermediate-risk prostate cancer—falls in between, with a PSA between 10 and 20 ng/dl, a clinical stage of T2b, and a Gleason 7 grade. Men with this kind of cancer are likely to benefit from treatment (surgery, radiation, seeds).
Questions to Ask Your Doctor
For a list of questions to ask your doctor when you’ve been diagnosed with prostate cancer, click here.